SQ2143 Datasheet, PDF (3/8 Pages) SeCoS Halbleitertechnologie GmbH – CMOS Positive Voltage Regula tor

Elektronische Bauelemente
SQ2143
CMOS Positive
Voltage Regulator
Ordering Information(contd.)
Part Number
SQ2143-AD
Marking
3DAD2
XXXX
Output Voltage
Adjustable
Part Number
Marking
Output Voltage
Detailed Description
The SQ2143 of COMS regulators contain a PMOS pass transistor,voltage reference, error amplifier,over-current protection and
thermal shutdown and Power Good function. The P-channel pass transistor receives data from the error amplifier,over-current shutdown,
and thermal protection circuits. During normal operation, the error amplifier compares the output voltage to a precision reference.
Over-current and Thermal shutdown circuits become active when the junction temperature exceeds150^oC,or the current exceeds 300mA.
During thermal shutdown, the output voltage remains low. Normal operation is restored when the junction temperature drops below 120^oC.
The SQ2143 switches from voltage mode to current mode when the load exceeds the rated output current. This prevents over-stress.
The SQ2143 also incorporates current fold-back to reduce power dissipation when the output is short circuited.This feature becomes active
when the output drops below 0.8 volts, and reduces the current flow by 65%. Full current is restored when the voltage exceeds 0.8 volts.
External Capacitors
The SQ2143 is stable with an output capacitance to ground of 2.2uF or greater. Ceramic capacitors have the lowest ESR, and will offer
the best AC performance. Conversely, Aluminum Elertrolytic capacitors exhibit the highest ESR, resulting in the poorest AC response.
Unfortunately, large value ceramic capacitors are comparatively expensive. One option is to parallel a 0.1 uF ceramic capacitor with a
10 uF Aluminum Electrolytic. The benefit is low ESR, high capacitance, and low overall cost. A second capacitor is recommended
between the input and ground to stabilize Vin. The input capacitor should be at least 0.1uF to have a beneficial effect. All capacitors
should be placed in close proximity to the pins. A "Quiet" ground termination is desirable . The can be achieved with a "Star" connection.
Enable
The Enable pin normally floats high. When actively, pulled low, the PMOS pass transistor shuts off, and all internal circuits are powered
down. In this state, the quiescent current is less than 1uA. This pin behaves much like an electronic switch.
ht tp://www.SeCoSGmbH.com/
01-Jun-2002 Rev. A
Any changing of specification will not be informed individual
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